Machine for manufacture of rotary cutting tools



April 7, 19.31. A. TSCHERNE 1,799,603

MACHINE FOR MANUFACTURE OF ROTARY CUTTING TOOLS Filed April 15, 1927 4 Sheets-Sheet 1 fig. 1.

April 1931- A. TSCHERNE 1,799,608

MACHINE FOR MANUFACTURE OF ROTARY CUTTING TOOLS Filed April 15-, 1927 4 Sheets-Sheet 2 fig. 7

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IACHINE FOR MANUFACTURE. OF ROTARY CUTTING TOOLS Filedz fiaril 13, 1927 4 Sheets-Sheet 5 April 7, 1931. A. TSCHERNE i 1,799,608

MACHINE FOR MANUFACTURE OF ROTARY CUTTING TOOLS Filed April 15, 1927 4 Sheets-Sheet 4 Patented Apr. 7,1931

FUN-15E"? starts 'ALOIS TSOHERNE, or aonso mon, swirznnnann MACHINE. FOR MANUFACTURE OEBOTARY CUTTING roots 7 Application filed April 13, 19'27, Serial No. 83,520, and in Switzerland and Germany February' l', 1927. 7

made is mounted on" a mandrel, Which latter is rotatable inv a reciprocating slide. The

slide is moved at right angles to the axis of l ber5 is capable of sliding ina slot 8 in an arm r rotation of a profile milling cutter or other tool, which tool cuts recesses in the blank. The shaft and with it the blank are rotated during the axial displacement of the blank to a greater or less degree, whilethe profile milling cutter passes from one end of the blank to the other, so that a recess is cut in the blank, the lateral edges of which are inclined to one another. These side walls of the recesses may be in a straight line or may follow a helical line. The rotary cutting tool (milling cutters and reamers) are preferably so made that each two successive cutting edges of the milling cutter, rea'mer or the like are at an angle to one another, i. e. are not equidistant from one another at either end. Cutting tools of this kind have the advantage that for the same expenditure of power they do more'work with a quieter drive. two constructional examples of the apparatus are shown in the accompanying drawings.

Fig. 1 shows one machine in plan view,

Fig. 2 in side elevation and 1 Fig. 3 in end elevation.

Figs. 4:, 5, 6, 7 8 show diagrammatically how the machine operates.

ter madeac'cording to this invention.

The machineshown in Figs. 1 to 10 isused in combination with a milling machine of a known kind, not shown in the draw1ngs.

The milling machine has a milling table T which is capable of sliding to and fro in a bed, above which table the milling spindle Z on which the milling cutter :H is mounted, is rotatably journalled, such that the axis which 'is capable of sliding vertically in capable of sliding. arms-and is provided with a' for ked partQQ;

In the embodiment of the invention,

Figs. 9-and 10 show parts of a milling cut- T. The table Tand the milling spi-ndle Z may be driven inany'known manner; On

the table T a casing 1 is fixed by screws. In 7 the casing 1 a hollow shaft 2 is mounted so as to rotate therein. To the hollow shaft 2 r a toothed segment 5 is rigidly 'fixe'd. 'WVith' the toothed segment 3 there'niieshes a rack 4 guidesinthe casing 1. On the rack 1454s mounted a pin 6 on which a sliding member 5 is rotatably mounted; Tlre-sliding;mem-

28 which ispivotedtoafpin 7 in-a-bear-ing Verse slide S of the milling macl1ine, i-n which transverse slide the lon'gitn'dinal sl ide"Tis- The lever' 28 has" two in which the sliding member 10 is capable of sliding. In-th'e sliding member 10 is the crank :pin 3'O of a crank disc l -1; The latter is mounted on'the shaft 14 which is jouri i-al led in ,the bearing 12. Theshaft "-ldiS drivem from the drive of the jmi'lli-ngspindle *Z'by means not shown in the drawing. 'ln the hollow spindle 2 aspindle 32 is rota tably journalled, to which a 'plafte1 6 is fixed. An 'arnrl afixed to the end' ofythe hollow spindle 2 carries apin"17wvhichcoactswiththe ho1es38 'e'fthe'diniding plate 16. Bymeans of the pin 17 the sha ft 3-2canbe1adj-u-sted with respect to the hollo w shaft 2, for I M determining the number of teeth ot-tl ie iii iil-l- 'ing cutter or the like being made. The blank A'lS fixed onamandrel 20 by means of nuts 21. The mandrel isheld between the centre 22of thespi-ndlef 2 and the l-iead stockcen'tre 23 The mandrel20 is connected {by anonpling sleeve 19 to the spindle32 in such a manner 'that the mandrel 2O gcannot :turn with respect to thespi'ndle 3E2.

'lTlZL'IlIlBI'i- -Afte'r'the'blank Al asibeenpl'aced between vini ll-ing cutter H. The slide "I is ithere'upoi'i' The machine operates in the following raised by the depth of the cut to be made in the blank H. The end surface I) of the blank A is the edge, at which the cut commences. In this position the sliding piece 5 which is rotatably journalled on the pin 6 of the rack 4 from the centre of rotation of the pin 7, in the groove 8 of the pivoted arm 28 by the amount of the thickness or length of the blank A. On the machine being engaged in motion, the shaft 14 which turns the crank pin 30 commences to rotate, causing the pivoted arm 28 to rock. The rack 4 which is connected to the pivoted arm 28 and guided in the casing 1 slides up and down and by means of the toothed segment 3 rocks the hollow spindle 2 to and fro and with it the blank A. At the same time the working slide T is moved towards the milling cutter H and, since, as described above, the blank A turns with the rocking motion of the arm 28 in the two directions 03, d, a broad recess f commencing at b will be cut in the blank A when the slide commences its forward motion. As the sliding member 5 in the groove 8 approaches the pivotal point of the rocking lever 28, in correspondence with the progresto continually increase or decrease the extent of movement of the said rack while the slide is being moved.

2. A machine for milling rotary cutting tools having their cutting edges extending longitudinally thereof comprising in combination a frame, a rotatably journalled milling spindle, a profiled milling cutter on said spindle, a slide adapted to slide at right angles to the said spindle, a shaft rotatably mounted in said slide, and adapted to receive the blank, means to oscillate said shaft in a constantly increasing or decreasing degree on the slide being advanced, said means comprising a spur wheel'connected to the said blank carrying shaft, a rack meshing with said spur wheel, a double armed lever, pivotally mounted in the frame,a slot in one arm of said double armed lever radial to the pivotal axis of said lever, a bolt on said rack engaging said slot, a guide by which the rack is held in its en agement with the spur wheel on the slide, and means for oscillating the lever constantly as the slide advances.

In witness whereof I afiix my signature.

ALOIS TSOHERNE.

sive forward feed of the slide T, the oscillat- Y ing motion of the blank A naturally becomes smaller and smaller and, when the pivotal pin 6 of the sliding member 5 is exactly opposite the pin 7 of the rocking lever 28 (Figs. land 2), the motion of the rack 4 and the rotary motion of the blank A become equal to zero. Owing to the fact that the sliding member 5 in the groove 8 of the rocking-arm 28, the pivotal point of which is stationary, approaches near and nearer to the pivotal point of the said arm, a groove f is cut in the blank A, the edges 0 and 0 of which are at an angle to one another and follow helical lines,

corresponding to the rocking angle to which the arm 28 is set. The edge 0 of the groove forms the cutting edge of the teeth while the edge 0 forms the back of the teeth, in accordance with the profile of the milling cutter H. The teeth cut in this way in the blank A have a uniform profile as denoted by the angles .2 and 2 (Fig. 8).

What I wish to secure by U. S. Letters Patent is 1. A machine for milling rotary cutting tools having their cutting edges extending longitudinally thereof comprising in combination a frame, a rotatably journalled milling spindle, a profiled milling cutter on said spindle', a slide adapted to slide at right angles to the said spindle, a shaft rotatably mounted in said slide, and adapted to receive the blank, means to oscillate said shaft in a constantly increasing or decreasing degree on the slide being advanced, saidfmeans comprising a spur wheel connected to the said blank carrying shaft, a rack meshing with said spur wheel, a double armed lever pivotally mounted'in the frame, engaging said rack, means 

